The Joint Research Team of Professor Ji Sun-Ha and Johns Hopkins University Presents Thesis in「NEJM」 Professor Jee, Sun-Ha’s research team of the Yonsei University Graduate School of Public Health, the National Health Insurance Corporation, and the research team of Johns Hopkins Bloomberg School of Public Health have jointly conducted the world’s largest scale epidemiology research since 1992. Their research subject were approximately 1.2 million people who received the health inspection that had been carried out by the National Health Insurance Corporation. Through this research, it has been confirmed that as the degree of obesity increases, there is a higher probability that cancer, cardiovascular, and cerebral diseases will develop. The research has closely examined for the first time that obesity is much more dangerous for middle-aged people than for senior citizens, that it is more desirable when the weight is lower, and that simply being underweight is not a health-threat in itself. The research results have been presented in the "New England Journal of Medicine (NEJM)" Internet site on August 24th. "NEJM" is the world’s most prestigious medical journal with an Impact Factor (IF) of 44 which is 10 units higher than that of "Nature" and "Science." 12-year A Followed-up on 1.2 million people, the World’s largest-scale epidemiology research Professor Jee, Sun-Ha’s research team traced and observed for 12 years approximately 1.2 million people who received the health inspection that was conducted by the National Health Insurance Corporation in order to research the correlation between weight and death. According to the research results, if the BMI (Body Mass Index) is higher, cancer frequency increases by an average of 1.5 times, and the frequency of cardiovascular and cerebral diseases increases by more than 2.4 times, with the death rate of cancer beginning to increase from around BMI 26.0~28.0, while the death rate due to cardiovascular and cerebral diseases appearing to continuously augment with the rise of BMI. The group with the lowest death rate was non-smokers who have a BMI between 23.0 and 25.0. This research has especially gained much attention from academia at home and abroad because it has refuted the preexisting theory that being underweight is a health threat for it can increase the risk of respiratory diseases. As a result of analyzing the causal relationship between being underweight and respiratory diseases, it has been found that the reason why people in the underweight group have a higher death rate is because their weight decreases as a result of suffering from respiratory diseases such as tuberculosis, chronic obstructive pulmonary disease, asthma, pneumonia etc. By proving that it is not the state of being underweight itself that has caused these respiratory diseases, they have brought closure to the controversy of "to what extent people should lose weight." Professor Jee has said that "The research will be an important indicator that will aid in establishing the obesity standards for Asians and in devising precautionary measures for cancer, cardiovascular and cerebral diseases." Furthermore he emphasized that "In the past, smoking had been recognized as the greatest health threat. However now the population of smokers has decreased and the obese population has increased, rendering obesity as the greatest health threat of the future."